Seismic indicators or anomalies such as flat spots, conformance, and amplitude versus offset (“AVO”) have been used in recent years to improve the estimation of the chance of success (“COS”) of segments and prospects. A “segment” generally refers to a discrete exploration target, and a prospect refers to a collection of segments. The “prospect chance of success” generally is the chance that at least one segment succeeds (i.e., has hydrocarbons) assuming that each of the segments in the prospect is drilled.
Several methods exist to handle these anomalies. At least one approach employs Bayesian Risk Modification (“BRM”). This approach allows the exploration team to take into account anomalies that increase the chance of success of a segment, and “false positive” anomalies, i.e., anomalies that are caused by a particular fluid condition inside the reservoir and that may be mistaken for hydrocarbon indicators. For this reason, these signals are generally regarded as direct fluid indicators (“DFIs”) and not as direct hydrocarbon indicators (“DHIs”).
A challenge when dealing with seismic anomalies is how the seismic information in multi-segment prospects should be valued.